1. Field of the Invention
The present invention relates to propulsion and control of underwater vehicles.
2. Discussion of the Background
Underwater vehicles, such as autonomous under water vehicles (or AUVs), are used to acquire various types of scientific data and water column characteristics in deep sea environments. In order to facilitate the collection of data, AUVs must be configured to include characteristics such as high speed, maneuverability, and energy efficiency, however present AUVs have not sufficiently provided such characteristics.
Known AUV configurations include underwater vehicles having propellers that are mounted to the vehicle such that the propeller rotates on an axis that has a fixed orientation with respect to the body of the AUV. Such AUVS typically include one or more rudder devices that pivot to control the direction of the AUV within the submerged environment. In this configuration the propeller provides forward thrust and the rudder devices directional control by providing wing-like or fin-like structures having surfaces that act against the fluid passing over the rudder devices. This configuration is inherently inefficient since the fluid pressure acting on the rudder devices in order to control the direction of the vehicle is effectively acting against the forward thrust of the propeller, thereby requiring the propeller motor to expend additional energy to steer the AUV. Additionally, the rudder devices are not necessarily the most efficient or accurate manner of controlling the direction of the AUV. Furthermore, the forces acting on the rudder devices require that the wing-like or fin-like structures be constructed of rigid materials that are likely heavier in weight and more expensive to manufacture than might otherwise be necessary.
Therefore, there is a need for a propulsion and control system for an underwater vehicle that is more efficient, more accurate, and less expensive to manufacture than known systems.
Accordingly, the present invention provides an assembly having an articulated, ducted thruster for improved underwater vehicle control and propulsion.
The present invention advantageously provides an assembly for an underwater vehicle that includes a motor, a duct assembly, and a first actuator. The duct assembly includes a duct and a propeller mounted within the duct, where the propeller is driven by the motor. The first actuator is connected to the duct assembly and is adapted to be connected to the vehicle. The first actuator is advantageously adapted to pivot the duct assembly with respect to the vehicle. Preferably, the assembly further includes a coupling member mounted to the vehicle and configured to pivotally receive a portion of the duct assembly, where the duct assembly is configured to pivot within the coupling member. Additionally, the assembly preferably includes a second actuator mounted to the vehicle, where the second actuator is connected to the coupling member and is adapted to pivot the coupling member with respect to the vehicle.
The present invention further advantageously provides an assembly for an underwater vehicle that includes a motor, a duct having a generally cylindrical shape oriented about a longitudinal axis, and a propeller having an axis of rotation. The propeller is mounted within the duct and is driven by the motor. The propeller and the duct are connected such that the axis of rotation of the propeller and the longitudinal axis of the duct have a fixed orientation with respect to one another. The assembly further advantageously includes a means for changing an orientation of the axis of rotation of the propeller and the longitudinal axis of the duct with respect to the vehicle.